Tutorial on Introduction to
biostatistics

Data compilation

Once the data is collected and validated it can then be
compiled. Tabulation is the basic method of compilation.

Data Analysis

Primary data analysis starts with the diagrammatic and
graphical representation of the data. The following are frequently used
methods:

A.
Histogram

B .Bar
Graph

C .Pie
chart

D. Line
graph

A. Histogram

Histograms consist of a series of
blocks or bars, each with an area proportional to the frequency.In a histogram the horizontal scale is used
for the variable and the vertical scale to show the frequency.

The highest block in a histogram
indicates the most frequent values. The lowest blocks show the least frequent
values.Where there are no blocks,
there are no results that correspond to those values.Blocks of equal height indicate that the values they represent
occur in the same frequency.

Age distribution of
patients in a cancer study

B. Bar Graph

In a simple bar
chart, each bar represents a different group of data. Although the bars may be
drawn either vertically or horizontally, it is conventional to draw the bars
vertically whenever possible. The height or length of the bar is drawn in
proportion to the size of the group of data being represented.Unlike a histogram, the bars are drawn
separated from one another.

Sex
wise distribution of patients in a cancer study

C. Pie Charts

Pie charts, or
circle graphs as they are sometimes known, are very different from other types
of graphs. They don't use a set of axes to plot points.Pie charts display percentages.

The circle of a
pie graph represents 100%. Each portion that takes up space within the circle
stands for a part of that 100%. In this way, it is possible to see how
something is divided among different groups.

D. Line graph

A Line
graph is drawn after plotting points on a graph that are then connected by a
line. Line graphs are useful to display data trends.